Question: $ { {3} \times \left[\begin{array}{rr}{-1} & {-1} \\ {3} & {3} \\ {-1} & {1}\end{array}\right] = {?} } $
Explanation: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{3}\times{-1} & {3}\times{-1} \\ {3}\times{3} & {3}\times{3} \\ {3}\times{-1} & {3}\times{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {-3} \\ {9} & {9} \\ {-3} & {3}\end{array}\right]}$